These items were donated by Glenn
Seaborg and identified by him as activated samples that he and John (Jack)
Livingood had produced
at the University of California in Berkeley. This would have been in
1936 to 1938 - one of the small boxes in which these came has "Oct 9
'37" indicated in Livingood's handwriting. Livingood
activated samples in a cyclotron and Seaborg separated out the elements
of interest. He then placed these preparations on cardboard and covered them
with cellophane. Livingood then analyzed the properties of the induced radioactivity with an
electroscope.

The writing on the cardboard holders (photo to right) is
as follows:

Top Row, left to right.

Sample 1:
"Co of Ni + n XII"

Sample 2:
"Co of Mn + He
V"

Sample 3:
"Co [of ?] Ni + D I"

Bottom row, left to right.

Sample 1: "[Sn of
?] Sn + D III"

Sample 2: "Co of
Mn + He VI"

Sample 3. "Zn
of Zn + D I"

Each sample holder is 1 1/4" wide (not counting the
small tab) and 2 1/2" long.

Let me use an example to explain what the
information on the cards indicates. In one important
experiment, Livingood bombarded an iron target with deuterons. This would
be symbolized Fe + D. Seaborg then dissolved the target and
chemically separated out three elements: iron (Fe), cobalt (Co), and
manganese (Mn). These three preparations would be indicated as Fe of Fe +
D, Co of Fe + D, and Mn of Fe + D respectively. While I am not sure
what the roman numeral at the end indicates, I suspect that it
refers to a particular experimental run.

Using this method, Seaborg and Livingood
discovered and characterized a number of radioisotopes including I-131,
Fe-55, Fe-59, Zn-65 and Co-60. I like to imagine, and it is possible, that some of these cards are associated with the discovery of Co-60.

Livingood would later say "It was a wonderful time. Radioactive elements fell in our laps as though we were shaking apples off a tree."

To give a
better idea of what was involved in these investigations, I will quote parts
of a presentation made by Seaborg at
the 1970 annual meeting of the Society of Nuclear Medicine:

"I
became involved in the discovery of a number of radioisotopes that in
subsequent years have found substantial applicants in the diagnosis and
treatment of disease. These include iodine-131, cobalt-60, technetium-99m,
iron-59, iron-55, cobalt-57, cesium-137, and zinc-65. of the 8,000,000
administrations per year of radioisotopes in the
United States
, some 90% utilize either iodine-131, cobalt-60 or technetium-99m."

"My collaborator in most of this work was a young
nuclear physicist, John J. Livingood. Our association extended over a
period of about five years (1936-1941) even though he left Berkeley to accept a position at HarvardUniversity near the end of 1938. the transmutation reactions
which led to the production of these radioisotopes were effected first
with the 27-inch cyclotron, which later became the 37-inch cyclotron, in
the old Radiation Laboratory, and finally with the 60-inch cyclotron in
the Crocker Laboratory."

"The
chemical work I performed during my continuing collaboration with Jack
while he was still in Berkeley was all done in this little corner of the
room in LeConte Hall. Our teamwork in every instance consisted of Jack's
performing the cyclotron bombardments, after which I dissolved the target
material and made the chemical separations. We next mounted the chemical
end products on cardboard sheets and covered these with thin cellophane.
He then measured their radiation characteristics [half-life, energy and type of emitted radiation], using a small Lauritsen
quartz fiber electroscope mounted in a sort of cubbyhole room in the
basement at the opposite end of LeConte Hall."

Seaborg dissolved the activated target in acid and separated out three elements - usually a rush job. First he precipitated out the target element (e.g., nickel) using a "carrier." The precipitate was collected on a filter and transferred to the cardboard card. He then used the appropriate carriers to precipitate two more elements: the element whose atomic number was one greater than the target (e.g., copper) and the element whose atomic number was one less than that of the target (e.g., cobalt). Seaborg commented "Easy for a chemist, but for most physicists [like Jack], an unfamiliar world].

"Our motivation in searching for new
radioisotopes was simply the fascination for exploring an exciting new
frontier of science. Usually we gave little thought to the possibility
that one of the objects of our search would have practical value."

"Our
first immediately practical jackpot came early in the collaboration
between me and Jack Livingood. We had learned that Professor George H.
Whipple of the
University
of
Rochester
was hoping to have a reasonably long-lived radioisotope of iron for use in
his studies of hemoglobin in human blood. A visiting chemist from
England
, Fred Fairbrother, had begun to collaborate with Livingood in the spring
of 1937 on this problem but his visit ended before completion of the work.
Livingood turned to me, and this was our second team effort."

"With some
advance warning, I was able to plan the chemical separation more
carefully, to guard against the mixed results from the hasty work with
tin. Jack bombarded iron with 5.5 MeV deuterons in the 27-inch cyclotron.
When the target came off the cyclotron, around dinner time as I remember,
my chemical set-ups were ready.In my
determination to make an extremely clean chemical separation into
fractions containing iron and the expected transmutation products cobalt
and manganese, I worked all night making precipitations and repeated
reprecipitations. When Jack came to work early in the morning just as the
sun was rising, I handed him the three fractions and he began his first
production run was made with the cyclotron, the resulting iron-59 was sent
by E.O. Lawrence to Dr. Whipple, who performed the first tracer
experiments on the blood, and these experiments opened up a new era in our
understanding of iron metabolism and blood formation."

"In the course of our investigation we also
bombarded cobalt with neutrons and found a very long-lived radioactive
isotope of cobalt, confirming the indications of others that such an
isotope existed, and our later work identified this as the now well-know
cobalt-60. Jack and I continued this line of investigation by bombarding
pure cobalt samples, some with neutrons and some with deuterons furnished
by the 27-ince cyclotron, followed by very careful chemical separation
experiments. These bombardments and chemical separations took place in the
summer of 1937, and by the spring of 1938 our decay and radiation
absorption measurements had pretty well established the radioactive
properties of cobalt-60 for which we eventually measured a half-live of
5.3 years."

"A similar pattern developed in our work on
zinc-65, also carried out in 1938 while Livingood was still in Berkeley. Here we followed up on the work of others who has
observed a radioisotope of zinc whit a half-life of about seven months
produced by the deuteron bombardment as well as the proton bombardment of
copper. Livingood prepared and bombarded a zinc target with8 MeV deuterons in the 37-inch cyclotron and I performed the
chemical separations which made it possible for us during 1938 to assign
this radioactivity to zinc-65, characterize its half-life as 250 ± 5
days, and to determine the energy of the radiations, with the help of
Jack’s measurements with his electroscope."

Glen Seaborg. Remarks by Dr. Glenn T.
Seaborg, Chairman U.S. Atomic Energy Commission at the 17th Annual Meeting
of the Society of Nuclear Medicine Washington, D.C. July 10, 1970.
"Reminiscences on the Development of Some Medically Useful
Radionuclides."